Hydraulic actuated alpha-frame derrick



July 3. 195 T. R. HALL HL'MHMEfi HYDRAULIC ACTUATED A-FRAME DERRICK Filed Dec. 22, 1952 2 Sheets-Sheet 1 IN V EN TOR.

Thomas R.Ha]]

July 3, 1956 T. R. H ALL HYDRAULIC ACTUATED A-FRAME DERRICK Filed D00. 22, 1952 2 Sheets-Sheet 2 M fi Z3 /6 H O I /8 II! I! 1 i I ll 1|-" I l I n I n s'i w it 151. 8.

INVENTOR. Thomas all Y United States Patent Ofiice 2,753,055 Patented July 3, 1956 12 Claims. (Cl. 212--8) assignor to American Portland, reg., a corporation of This invention pertains to folding, portable derricks or booms, particularly useful on trucks of the type used by public utility companies for the erection and maintenance of poles on which overhead lines are carried.

There are many existing types of portable derricks adapted to be carried on trucks. In order to transport such derricks along highways and streets, it is necessary that the structure be collapsible to lie flat on the top of the truck. The derrick structures are usually heavy and cumbersome and do not permit ready erection or taking down by means of hand power. Customarily, the derrick parts are of telescoping or folding construction and may be moved into or out of erected position by means of a hoisting line which is reeved over a sheave at the apex of the derrick construction and the hoisting line is driven by a winch on the truck. Once the derrick has been erected, the winch and hoisting line are used to lift and lower the loads to be carried by the derrick. The winch is usually driven from the main drive shaft of the trucks engine and a rather complicated clutching arrangement between the shaft and winch is necessary in order to provide the necessary selective manipulation of the hoisting device.

The object of the present invention is to provide a simple, strong, relatively inexpensive, portable derrick.

According to a feature of the invention, the Winch and hoisting line customarily used are done away with and a piston and cylinder arrangement is substituted therefor which takes care not only of erecting and taking down the derrick but lifting and lowering loads to be carried thereby when in erected position.

Other novel features of my invention reside in the manner in which the parts of the derrick are mounted on the truck and may be 'folded into smaller compass, and the manner in which the piston-andcylinder are con nected and operate with the other parts.

These and other features of .my invention will be brought out more clearly in the following detailed .description, taken in connection with the accompanying drawings, in which:

Fig. 1 is a top plan view of a truck with the derrick constructed in accordance with the invention thereon;

Fig. 2 is a side elevation, partly broken away, of the truck and derrick shown in Fig. 1;

Fig. 3 is a side elevation showing the derrick in partially erected position;

Fig. 4 is a side elevation showing the derrick in erected position;

Fig. 5 is a schematic diagram of the piston and cylinder;

Fig. 6 is a rear elevation of a truck showing an alternative construction of the derrick;

Fig. 7 is a side elevation showing the alternative construction of the derrick; and

Fig. 8 is a side elevation of the derrick in erected position.

A truck 1 supports an articulated derrick or boom which comprises an A-frame having two side or shear showing the operation shown in Fig. 7

legs 2 and 3 which are upwardly converging. A middle or bracing leg 4 is located between legs 2 and 3, and the three legs 2, 3 and 4 converge and their upper ends meet at the apex of the frame where they are held together by a pivotal connection 5.

When the derrick is in folded or lowered position and not in use, legs 2, 3 and 4 rest on a suitable supporting brace 6 provided on the top of the truck, the apex of the A-frame being positioned above cab 7 of the truck and the bases of the legs over the rear of the truck.

Thelower ends of legs 2 and 3 are pivotally connected by pins 8 to collars 9, which surround the top of each of base or support leg portions 10 and 11. Base legs 10 and lit are pivotally connected by pins 12 to plates 13 fastened to the body of truck 1 and may be locked in place by latches 14 extending from either side of the truck.

Bracing leg 4 is connected at its lower end to a piston 16 by a collar and pivot pin 17. Piston 16 operates within a cylinder 18 which is pivotally mounted in the truck on a pin 19 fastened to a plate on the truck body.

Piston i6 is preferably hydraulically operated as diagrammatically shown in Fig. 5, although it is to be understood that the piston could be driven by some other suitable source of power. Oil in sump 20 is circulated through the supply lines in the system by oil pump 21. A four-way valve 2.2 may be operated and locked in position by handle 23 to direct oil pressure into the cylinder against either end of piston 16 to move the piston a desired distance in or out of the cylinder chamber.

A pair of links 24 are pivotally connected to either side of cylinder 18 by pins 25 and to the lower end of leg 4 by pins 26.

To erect the derrick so that it position, the constituent parts are moved through a plurality of positions. When valve 22 is operated .to move piston is from its at rest position, leg 4 will be pivoted about pins 25 and raised into the position shown in Fig. 3. Legs 2 and 3, which are secured by plate 5 to leg 4, will also be carried up pivoting about pins 8, since their base portions 10 and 11 are fixed in place by latches i4. Piston l6 continues to be operated until legs 2 and 3 are in their completely raised position and bracing leg l is also in position between legs 2 and 3 but in back thereof as seen in Fig. 4. Legs 2 and 3 are then locked to their respective base portions 10 and 11 by means of upper collars 27 fastened to the upper ends of base portions it) and ill and adapted to surround legs 2 and 3 and be locked thereto by pins 28. In this manner, legs Zand 3 and their respective base leg portions 10 and 11 are held in rigid alignment. Another collar and pin attachment 2% at the bottom of leg 4 is fastened to piston '16 to hold it in rigid alignment with leg 4. Pins 26 holding links 24 to leg 4 are removed and the links swung down out of the way into dotted line position as shown by the arrows in Fig. 4. Latches 14 holding legs lil and 11 in place are released and swung up as shown in dotted lines. The derrick is now fully raised and in operative position. A hook 3t) and chain 3]. are fastened through hole 32 of the apex of the A-frame. If it is desired to lower the derrick to pick up a load on the hook, piston 16 is moved out and leg 4 will pivot about pin l9 and legs 2 and 3 about pins 12 and the whole derrick will be swung through the are shown by the arrows to the position shown in dotted lines in Fig. 4. Thus it will be seen that the derrick may be operated to assume substantially any position between 0 and with the ground.

In an alternative construction shown in Figs. 7 and 8, the links 24 previously shown are replaced by a link 33 and a bar 34 extending across the back of the truck. This bar is sometimes referred to as a head knocker, since will be in operative workmen getting on and off the truck frequently bump their heads against it and this is one reason that its elimination is desirable. Link 33 is pivotally connected at one end by pin 35 to plate 36 and at the other end by collar 37 and pin 38 to leg 4. After the legs have been moved into the raised position shown in Fig. 7, pin 38 is disengaged from link 33 which is swung down as shown by arrows and the piston and leg 4 are moved into the position shown where they as well as the other legs are held in rigid alignment in the same manner as described with relation to Figs. 3 and 4.

Thus it will be seen that the derrick according to my invention is of simple, rugged and portable construction. The parts permit easy folding and storage of the derrick into a compact ensemble as well as quick assembly into an operative structure. A single, positive driving means the piston-and-cylinder element-has been substituted for the usual winch and hoisting line. The piston and cylinder not only erect and take down the derrick, but raise and lower the derrick, thereby carrying out the load lifting function of the device.

I claim:

1. In combination with a mobile truck having a body, a folding derrick of A-frame construction adapted in folded position to rest on said body, said derrick including two shear legs and a bracing leg, said three legs being fastened together at the apex of the A-frame, a pair of shear leg supporting members pivotally mounted on the truck body, means for fastening each supporting member to a companion shear leg in rigid alignment, and a piston and cylinder having one end fastened to said bracing leg and the other end pivotally mounted on the truck.

2. The device according to claim 1 and link means connecting said piston to the bracing leg and means for fastening the piston and bracing leg in rigid alignment.

3. The device according to claim 1 and latch means for locking said shear leg supporting members to the body of the truck.

4. The device according to claim 1 and in which link means are connected at one end to the cylinder and at the other end releasably connected to the bracing leg.

5. The device according to claim 1 and in which a link is connected at one end to the body of the truck and at the other end releasably connected to the bracing leg.

6. In combination with a truck having an elongated body, a folding A-frame derrick adapted to overlie said body in a storage position and to extend out from one end of said body in an operative position, said derrick having two shear legs joined at an apex and bracing leg means pivotally joined to the shear legs adjacent the apex, a spaced pair of elongated shear leg supports mounted adjacent said truck body one end and pivotally carrying said shear legs on the upper ends thereof, piston and cylinder means pivotally mounted intermediate the ends of said truck body and pivotally carrying said brac- 4 ing leg means upon the upper end thereof selectively to erect and operate the derrick, and detachable means for fastening said piston and cylinder means to said bracing leg means in rigid alignment.

7. A folding A-frame derrick comprising a base, a pair of legs each leg being pivotally mounted at one end and joined at the other end to a companion end of the other leg element, a bracing member pivotally joined at one end to said pairs of legs adjacent the joined ends of the latter, and pivotally mounted at the other end upon said base, said bracing member comprising two sections pivotally joined together by a pivot, one of said bracing member sections comprising a piston-and-cylinder element to vary the overall length of said bracing member, whereby, when said piston-and-cylinder element is extended, said bracing member first moves from folded position to unfolded position, carrying therewith the joined pair of legs, and thereafter swings said derrick as a whole about the pivotally mounted ends of said pair of leg members and the bracing member, respectively.

8. Claim 7 modified in that operating means span the pivot joining the two bracing member sections.

9. Claim 7 modified in that detachable operating means span the pivot joining the two bracing member sections.

10. Claim 7 modified in that detachable means inhibit said pair of leg members from swinging past a predetermined angular position until said bracing member is unfolded.

11. Claim 7 modified in that releasable locking means hold the bracing member sections in rigid alignment when said bracing member is unfolded.

12. Claim 7 modified in that operating means span the pivot joining the two bracing member sections, detachable latching means inhibit said pair of leg members from swinging past a predetermined angular position until said bracing member is unfolded, and releasable locking means hold the bracing member sections in rigid alignment when said bracing member is unfolded.

References Cited in the file of this patent UNITED STATES PATENTS 2,173,421 Krezeminsky Sept. 19, 1939 2,364,851 Johansen Dec. 12, 1944 2,433,598 Chadwick Dec. 30, 1947 2,451,223 Johansen Oct. 12, 1948 2,541,970 Pospisil Feb. 13, 1951 2,557,192 Leister June 19, 1951 2,557,466 Richards et a1. June 19, 1951 2,595,307 Selberg May 6, 1952 2,601,927 Frenzel July 1, 1952 2,611,580 Troche et a]. Sept. 23, 1952 2,613,822 Stanley Oct. 14, 1952 FOREIGN PATENTS 486,501 Canada Sept. 16, 1952 

